Add command and code action to extract into function and local variab…

…le (#2139)

src/goDoctor.ts

@@ -0,0 +1,103 @@
+/*---------------------------------------------------------
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------*/
+
+'use strict';
+
+import vscode = require('vscode');
+import cp = require('child_process');
+import { getBinPath, getToolsEnvVars } from './util';
+import { promptForMissingTool } from './goInstallTools';
+import { dirname, isAbsolute } from 'path';
+
+/**
+ * Extracts function out of current selection and replaces the current selection with a call to the extracted function.
+ */
+export function extractFunction() {
+	extract('extract');
+}
+
+/**
+ * Extracts expression out of current selection into a var in the local scope and
+ * replaces the current selection with the new var.
+ */
+export function extractVariable() {
+	extract('var');
+}
+
+type typeOfExtraction = 'var' | 'extract';
+
+async function extract(type: typeOfExtraction): Promise<void> {
+	let activeEditor = vscode.window.activeTextEditor;
+	if (!activeEditor) {
+		vscode.window.showInformationMessage('No editor is active.');
+		return;
+	}
+	if (activeEditor.selections.length !== 1) {
+		vscode.window.showInformationMessage(
+			`You need to have a single selection for extracting ${type === 'var' ? 'variable' : 'method'}`
+		);
+		return;
+	}
+
+	const newName = await vscode.window.showInputBox({
+		placeHolder: 'Please enter a name for the extracted variable.'
+	});
+
+	if (!newName) {
+		return;
+	}
+
+	runGoDoctor(
+		newName,
+		activeEditor.selection,
+		activeEditor.document.fileName,
+		type
+	);
+}
+
+/**
+ * @param newName name for the extracted method
+ * @param selection the editor selection from which method is to be extracted
+ * @param activeEditor the editor that will be used to apply the changes from godoctor
+ * @returns errorMessage in case the method fails, null otherwise
+ */
+function runGoDoctor(
+	newName: string,
+	selection: vscode.Selection,
+	fileName: string,
+	type: typeOfExtraction
+): Thenable<void> {
+	const godoctor = getBinPath('godoctor');
+
+	return new Promise((resolve, reject) => {
+		if (!isAbsolute(godoctor)) {
+			promptForMissingTool('godoctor');
+			return resolve();
+		}
+
+		cp.execFile(
+			godoctor,
+			[
+				'-w',
+				'-pos',
+				`${selection.start.line + 1},${selection.start.character +
+				1}:${selection.end.line + 1},${selection.end.character}`,
+				'-file',
+				fileName,
+				type,
+				newName
+			],
+			{
+				env: getToolsEnvVars(),
+				cwd: dirname(fileName)
+			},
+			(err, stdout, stderr) => {
+				if (err) {
+					vscode.window.showErrorMessage(stderr || err.message);
+				}
+			}
+		);
+	});
+}

src/goInstallTools.ts

@@ -41,6 +41,7 @@ const allToolsWithImportPaths: { [key: string]: string } = {
 	'go-langserver': 'github.com/sourcegraph/go-langserver',
 	'dlv': 'github.com/go-delve/delve/cmd/dlv',
 	'fillstruct': 'github.com/davidrjenni/reftools/cmd/fillstruct',
+	'godoctor': 'github.com/godoctor/godoctor',
 };
 
 function getToolImportPath(tool: string, goVersion: SemVersion) {
@@ -132,7 +133,8 @@ function getTools(goVersion: SemVersion): string[] {
 		'gomodifytags',
 		'impl',
 		'fillstruct',
-		'goplay'
+		'goplay',
+		'godoctor'
 	);
 
 	return tools;
@@ -164,7 +166,8 @@ export function installAllTools(updateExistingToolsOnly: boolean = false) {
 		'staticcheck': '\t(Linter)',
 		'go-langserver': '(Language Server)',
 		'dlv': '\t\t\t(Debugging)',
-		'fillstruct': '\t\t(Fill structs with defaults)'
+		'fillstruct': '\t\t(Fill structs with defaults)',
+		'godoctor': '\t\t(Extract to functions and variables)'
 	};
 
 	getGoVersion().then((goVersion) => {

src/goMain.ts

@@ -44,6 +44,7 @@ import { runFillStruct } from './goFillStruct';
 import { parseLiveFile } from './goLiveErrors';
 import { GoReferencesCodeLensProvider } from './goReferencesCodelens';
 import { implCursor } from './goImpl';
+import { extractFunction, extractVariable } from './goDoctor';
 import { browsePackages } from './goBrowsePackage';
 import { goGetPackage } from './goGetPackage';
 import { GoDebugConfigurationProvider } from './goDebugConfiguration';
@@ -55,6 +56,7 @@ import { installCurrentPackage } from './goInstall';
 import { setGlobalState } from './stateUtils';
 import { ProvideTypeDefinitionSignature } from 'vscode-languageclient/lib/typeDefinition';
 import { ProvideImplementationSignature } from 'vscode-languageclient/lib/implementation';
+import { GoRefactorProvider } from './goRefactor';
 
 export let buildDiagnosticCollection: vscode.DiagnosticCollection;
 export let lintDiagnosticCollection: vscode.DiagnosticCollection;
@@ -271,6 +273,7 @@ export function activate(ctx: vscode.ExtensionContext): void {
 
 
 	ctx.subscriptions.push(vscode.languages.registerCodeActionsProvider(GO_MODE, new GoCodeActionProvider()));
+	ctx.subscriptions.push(vscode.languages.registerCodeActionsProvider(GO_MODE, new GoRefactorProvider()));
 	ctx.subscriptions.push(vscode.languages.registerCodeLensProvider(GO_MODE, testCodeLensProvider));
 	ctx.subscriptions.push(vscode.languages.registerCodeLensProvider(GO_MODE, referencesCodeLensProvider));
 	ctx.subscriptions.push(vscode.debug.registerDebugConfigurationProvider('go', new GoDebugConfigurationProvider()));
@@ -324,6 +327,12 @@ export function activate(ctx: vscode.ExtensionContext): void {
 	ctx.subscriptions.push(vscode.commands.registerCommand('go.impl.cursor', () => {
 		implCursor();
 	}));
+	ctx.subscriptions.push(vscode.commands.registerCommand('go.godoctor.extract', () => {
+		extractFunction();
+	}));
+	ctx.subscriptions.push(vscode.commands.registerCommand('go.godoctor.var', () => {
+		extractVariable();
+	}));
 
 	ctx.subscriptions.push(vscode.commands.registerCommand('go.test.cursor', (args) => {
 		const goConfig = vscode.workspace.getConfiguration('go', vscode.window.activeTextEditor ? vscode.window.activeTextEditor.document.uri : null);

src/goRefactor.ts

@@ -0,0 +1,36 @@
+/*---------------------------------------------------------
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------*/
+
+'use strict';
+
+import vscode = require('vscode');
+
+export class GoRefactorProvider implements vscode.CodeActionProvider {
+	public provideCodeActions(
+		document: vscode.TextDocument,
+		range: vscode.Range,
+		context: vscode.CodeActionContext,
+		token: vscode.CancellationToken
+	): vscode.ProviderResult<vscode.CodeAction[]> {
+		const extractFunction = new vscode.CodeAction(
+			'Extract to function in package scope',
+			vscode.CodeActionKind.RefactorExtract
+		);
+		const extractVar = new vscode.CodeAction(
+			'Extract to variable in local scope',
+			vscode.CodeActionKind.RefactorExtract
+		);
+		extractFunction.command = {
+			title: 'Extract to function in package scope',
+			command: 'go.godoctor.extract'
+		};
+		extractVar.command = {
+			title: 'Extract to variable in local scope',
+			command: 'go.godoctor.var'
+		};
+
+		return [extractFunction, extractVar];
+	}
+}